Introduction to the Semantic Web - Vision and Technologies

Understand and articulate the semantic web vision. Know the basic framework and core technologies. Be aware of some available tools. Understand how mature the technology is and how you might (or might not) use it today. Get involved for further learning, contribution, or just plain geek fun.

Protégé is a free , open source ontology editor and knowledge-base framework. Developed by Stanford Medical Informatics with support from DARPA and others A cool tool – even if you could care less about the semantic web A bit of a learning curve, but great fun! You may never use a relational database for personal stuff again Screenshots follow…

Classes view shows a class tree of the classes in your ontology. Properties tab shows a list of property objects in your ontology. Navigator shows a list of ontologies used in each project; user can switch between them.

Lay-out is automatic, but a user can adjust the diagram by moving each class. Black arrows are subclass relationship Blue arrows show other relationships between classes, e.g., restrictions

Haystack Semantic Web Browser - A “Semantic Desktop” Concept Eclipse based Information in One Place Right Click on Anything Work with Information, Not Programs Drag and Drop E-mail and Instant Messaging Together Personal Digital Library And more…

Search Today’s search engines are based primarily on word occurrence They do not reason on data nor infer meaning Search is augmented with advertisements, not meaningful data relationships “ Yo-Yo Ma” might get augmented with his current concert schedule, his music albums, his image, etc. Combining data (personal, company, web) from disparate sources with reduced or no API programming. Software cannot easily leverage search automatically as a background process Desktop Application Integration Too many apps and too much propriety to expect well-orchestrated standards. Need “serendipitous interoperability”. Ubiquitous Computing The key issue (and goal) of ubiquitous computing is &amp;quot;serendipitous interoperability,&amp;quot; interoperability under &amp;quot;unchoreographed&amp;quot; conditions, i.e., devices which weren&apos;t necessarily designed to work together (such as ones built for different purposes, by different manufacturers, at a different time, etc.) should be able to discover each others&apos; functionality and be able to take advantage of it. Being able to &amp;quot;understand&amp;quot; other devices, and reason about their services/functionality is necessary, since full-blown ubiquitous computing scenarios will involve dozens if not hundreds of devices, and a priori standardizing the usage scenarios is an unmanageable task.

Transcript of "Introduction to the Semantic Web - Vision and Technologies"

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Software and Information Architects <ul><li>Session Objectives </li></ul><ul><li>After completing this session, </li></ul><ul><li>you should be able to: </li></ul><ul><ul><li>Understand and articulate the semantic web vision </li></ul></ul><ul><ul><li>Know the basic framework and core technologies </li></ul></ul><ul><ul><li>Be aware of some available tools </li></ul></ul><ul><ul><li>Understand how mature the technology is and how you might (or might not) use it today </li></ul></ul><ul><ul><li>Get involved for further learning, contribution, or just plain geek fun </li></ul></ul>

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The semantic web is… <ul><li>A vision for the future web (a ‘web of meaning’ - semantics ) </li></ul><ul><ul><li>Not a separate web but an extension of the current one </li></ul></ul><ul><ul><li>Better enabling computers and people to work in cooperation </li></ul></ul><ul><ul><li>Machine reasoning will be ubiquitous and powerful </li></ul></ul><ul><li>An emerging set of standards, markup languages, and related processing tools </li></ul><ul><li>A rolling snowball </li></ul><ul><ul><li>Interest and momentum is building fast - heads up! </li></ul></ul>Currently under the direction of Tim Berners-Lee (a.k.a. “father of the Web”) http://www.w3.org/2001/sw/ The Semantic Web Activity

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Notable points <ul><li>Distributed Extensibility </li></ul><ul><ul><li>Different sites may contribute data about a particular resource </li></ul></ul><ul><ul><li>We can all extend the cumulative knowledge on the Semantic Web about any resource in a distributed fashion </li></ul></ul><ul><li>A version of RSS , the famous syndication (content feeds) format is a sub-set of RDF </li></ul><ul><li>IBM case-in-point: </li></ul><ul><ul><li>The new RSS Consumer being developed for WebSphere Web Content Management (WCM) leverages the extensibility of RDF to add special elements into the standard RSS. </li></ul></ul><ul><ul><li>This allows for integration with other Content Management Systems like Interwoven and Vignette. </li></ul></ul>

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Ontology <ul><li>A formal way to organize knowledge and terms. </li></ul><ul><li>Typically represented as graphical relationships or networks, as opposed to taxonomies which are usually represented hierarchically. </li></ul><ul><li>Defines a domain of knowledge </li></ul><ul><ul><li>The objects that exist in that domain </li></ul></ul><ul><ul><li>The properties those objects can have </li></ul></ul><ul><ul><li>The relationships those objects and their properties can have to other objects and properties (in the same domain or across domains) </li></ul></ul><ul><li>What are the differences between a vocabulary, a taxonomy, a thesaurus, an ontology, and a meta-model? </li></ul><ul><ul><li>See: http://www.metamodel.com/article.php?story=20030115211223271 </li></ul></ul>“ An ontology is an explicit specification of a conceptualization.” - T. R. Gruber (…whatever…)

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OWL Web Ontology Language <ul><li>Designed for use by applications that need to process the content of information instead of just presenting information to humans. </li></ul><ul><li>Has three increasingly-expressive sublanguages: OWL Lite, OWL DL, and OWL Full. </li></ul><ul><li>OWL adds more vocabulary for describing properties and classes on top of RDF. Example: </li></ul><ul><ul><li>Disjointness </li></ul></ul><ul><ul><ul><li>Man and Woman are Disjoint Classes. Joan is an instance of Woman => Joan is not an instance of Man. </li></ul></ul></ul><ul><ul><li>Cardinality </li></ul></ul><ul><ul><ul><li>Person has exactly one value for the property hasBirthMother </li></ul></ul></ul><ul><ul><li>Equality </li></ul></ul><ul><ul><ul><li>Bill Clinton is sameAs William Jefferson Clinton </li></ul></ul></ul><ul><ul><li>Symmetry </li></ul></ul><ul><ul><ul><li>Frank is a friend of Deborah => Deborah is a friend of Frank. </li></ul></ul></ul>Yep…the acronym should be ‘WOL’, but the creators thought ‘OWL’ was much cooler.

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Some Lessons Learned <ul><li>No “right” way to model an ontology. </li></ul><ul><ul><li>Depends upon the end-use cases you have in mind </li></ul></ul><ul><ul><li>Depends on whether you intend to reason (engine) and auto-classify </li></ul></ul><ul><ul><li>Depends on personal preferences </li></ul></ul><ul><ul><li>1-2 weeks of playing with Protégé and learning about OWL </li></ul></ul><ul><ul><li>Rebuilt ontology up to 3 times before starting to code </li></ul></ul><ul><li>Wanted a dynamic model so that you can change ontology only without recoding application </li></ul><ul><ul><li>Ended up generating Java objects from ontology using Protégé OWL’s Java code generation feature (lazy, I guess) </li></ul></ul><ul><ul><li>Totally dynamic model is still doable (perhaps I should have used Jena OWL API?) Need more time. </li></ul></ul><ul><li>Ontology + auto generate Java model + Java Server Faces + Rational = Drag and drop development and very little code! </li></ul><ul><li>Discovered IBM Research projects after-the-fact </li></ul><ul><ul><li>Wish I would have used our stuff; some of it is very cool </li></ul></ul><ul><li>Total time = 2 months learning and experimenting (off-time) </li></ul><ul><ul><li>Now “I get it”…and want to start over. </li></ul></ul>

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Ready for prime time? <ul><li>Data modeling </li></ul><ul><ul><li>YES </li></ul></ul><ul><ul><li>Ontology-based approach to data modeling is highly beneficial </li></ul></ul><ul><li>Horizontal integration (breaking down &quot;silos&quot;) </li></ul><ul><ul><li>YES, sort of… </li></ul></ul><ul><ul><li>The tools are there, but they aren’t baked in to many enterprise products </li></ul></ul><ul><ul><li>Concepts may be “too new” for customer comfort </li></ul></ul><ul><ul><li>Opportunity for IBM to take a stronger leadership role. </li></ul></ul><ul><li>Machine-driven interpretation (i.e. inference, rules engines, etc.) </li></ul><ul><ul><li>NO </li></ul></ul><ul><ul><li>Not mature, slow, or based on rapidly evolving standards </li></ul></ul><ul><ul><li>A big pill to swallow at first; learn the basics before getting into inference, rules, and reasoning. </li></ul></ul><ul><li>CONCLUSION: </li></ul><ul><ul><li>“ Semantic Web” as a concept may not be ready for prime time, but it is ready for our attention </li></ul></ul><ul><ul><li>Many semantic web technologies are mature and immediately beneficial </li></ul></ul><ul><ul><li>Learning curve is rather steep (or I’m slow) – get started! </li></ul></ul>

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@ IBM <ul><li>Semantics on AlphaWorks </li></ul><ul><ul><li>http://www.alphaworks.ibm.com/topics/semantics </li></ul></ul><ul><ul><li>Flash Demos: http://www.alphaworks.ibm.com/demo/flash/wssem </li></ul></ul><ul><li>Semantic Tools for Web Services </li></ul><ul><ul><li>http://w3.alphaworks.ibm.com/techs/alphabrief.jsp?tech=wssem </li></ul></ul><ul><ul><li>A set of Eclipse plug-ins for semantic matching and composition of Web services. (This is an ETTK technology.) </li></ul></ul><ul><li>Semantic Layer Research Platform </li></ul><ul><ul><li>On IBM Internal Open Source Bazaar </li></ul></ul><ul><ul><li>http://w3.opensource.ibm.com/projects/slrp/ </li></ul></ul><ul><ul><li>A platform for building Semantic applications that use RDF, LSID and other Semantic Web technologies. The platform includes several components such as an RDF server with collections, acls, replication and transactions, client and web development kits including an Eclipse suite of plugins for RDF consumption. This project also contains several prototypes such as Life Sciences Workbench and Unified Activity Management. </li></ul></ul><ul><li>Semantic Super Computing </li></ul><ul><ul><li>On IBM Internal Open Source Bazaar </li></ul></ul><ul><ul><li>http://w3.opensource.ibm.com/projects/ssc/ </li></ul></ul><ul><ul><li>The Semantic Super Computing project performs research on large amount of data or large amount of computation. The aim is to explore innovative way to deal with the scalability issues and user interface problems of such projects. </li></ul></ul><ul><li>Watson Research Semantics Wiki </li></ul><ul><ul><li>http://semanticswiki.watson.ibm.com/FrontPage </li></ul></ul><ul><li>Blue Pages </li></ul><ul><ul><li>Search entire profile for “Semantic Web” </li></ul></ul><ul><ul><li>39 results as of 1/31/2006 </li></ul></ul>

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Session Summary <ul><li>Now that you have completed this session, you should be able to: </li></ul><ul><ul><li>Understand and articulate the semantic web vision </li></ul></ul><ul><ul><li>Know the basic framework and core technologies </li></ul></ul><ul><ul><li>Be aware of some of available tools </li></ul></ul><ul><ul><li>Understand how mature the technology is and how you might (or might not) use it today </li></ul></ul><ul><ul><li>Get involved for further learning, contribution, or just plain geek fun </li></ul></ul>